English Medium कक्षा १० - CBSE Question Bank Solutions for Science

 Explain why, a food chain usually cannot have more than three or four steps.

Calculate the amount of energy that will be available to big fish in the following food chain, if 10,000 J of energy is available to small algae from the sun :
Small algae → Zooplankton → Fish → Big fish

Name and state the law given by Lindeman which tells us how much energy entering a particular trophic level of organisms is available for trasnsfer to the next higher trophic level.

How much energy will be available to hawks in the food chain comprising hawk, snake, paddy and mice, if 10,000 J of energy is available to paddy from the sun?

On what basis is a chemical equation balanced?

What provides the energy which then flows through a food chain?
(a) glucose
(b) oxygen
(c) respiration
(d) sunlight

In the food chain given below, if the amount of energy available at fourth trophic level is 5 kJ, what was the energy available at the producer level?
Grass → Grasshopper → Frog → Snake → Hawk
(a) 500 kJ
(b) 50 kJ
(c) 5000 kJ
(d) 5 kJ

Which of the following limits the number of trophic levels in a food chain?
(a) insufficient food supply from producer level
(b) decrease in energy at higher trophic levels
(c) increase in the number of organisms at higher trophic levels
(d) accumulation of harmful chemicals at higher trophic levels

What percentage of sun's energy falling on the leaves of green plants is utilised by the plants in the process of photosynthesis and stored as chemical energy of food?
(a) 99 per cent
(b) 10 per cent
(c) 1 per cent
(d) 20 per cent

State whether the following statement is true or false:
A chemical equation can be balanced easily by altering the formula of a reactant or product.

What is wrong with the following chemical equation?

Mg   +   O   →   MgO

Correct and balance it.

What does the symbol (aq) represent in a chemical equation?

Which of the following gets the minimum energy through the food chain in an ecosystem?
(a) carnivore
(b) large carnivore
(c) producer
(d) herbivore

A food chain comprises of cat, seed-eating bird, plants, and dog. The organism which will have the maximum concentration of harmful pesticides coming through the food chain is most likely to be :
(a) cat
(b) plants
(c) dog
(d) seed-eating bird

An aquatic food chain comprises of the organisms like tadpoles, weeds, fish and water beetles. The organism which gets the minimum energy through this food chain is :
(a) water beetles
(b) tadpoles
(c) weeds
(d) fish

Most of the water surface of a lake is covered with algae. This algae is part of the food chain which also includes small fish, bird, larvae and big fish. Which of the following will obtain the maximum energy?
(a) big fish
(b) bird
(c) larvae
(d) small fish

If the energy available at the producer level in a food chain is 150 J, how much energy will be transferred to : tertiary consumer?
(a) 15 J
(b) 10 J
(c) 1.50 J
(d) 0.15 J

How will you indicate a solution made in water in a chemical equation?

How will you indicate Exothermic reaction in a chemical equation?

How will you indicate Endothermic reaction in a chemical equation?